Add debugging information in case of SSH connection error

In case of SSH error, new debugging information is added to the log:
- The local routing table
- The local ARP table

Change-Id: Ibe83390402675bb7e7d3cc4909a8097de4b0f836
Related-Bug: #1858642

neutron_tempest_plugin/common/ip.py

@@ -15,6 +15,7 @@
 #    under the License.
 
 import collections
+import re
 import subprocess
 
 import netaddr
@@ -299,6 +300,23 @@ def _get_ip_address_prefix_len_pairs(port, subnets):
                    netaddr.IPNetwork(subnet['cidr']).prefixlen)
 
 
+def arp_table():
+    # 192.168.0.16  0x1  0x2  dc:a6:32:06:56:51  *  enp0s31f6
+    regex_str = (r"([^ ]+)\s+(0x\d+)\s+(0x\d+)\s+(\w{2}\:\w{2}\:\w{2}\:\w{2}\:"
+                 r"\w{2}\:\w{2})\s+([\w+\*]+)\s+([\-\w]+)")
+    regex = re.compile(regex_str)
+    arp_table = []
+    with open('/proc/net/arp', 'r') as proc_file:
+        for line in proc_file.readlines():
+            m = regex.match(line)
+            if m:
+                arp_table.append(ARPregister(
+                    ip_address=m.group(1), hw_type=m.group(2),
+                    flags=m.group(3), mac_address=m.group(4),
+                    mask=m.group(5), device=m.group(6)))
+    return arp_table
+
+
 class Route(HasProperties,
             collections.namedtuple('Route',
                                    ['dest', 'properties'])):
@@ -314,3 +332,19 @@ class Route(HasProperties,
     @property
     def src_ip(self):
         return netaddr.IPAddress(self.src)
+
+    def __str__(self):
+        properties_str = ' '.join('%s %s' % (k, v)
+                                  for k, v in self.properties.items())
+        return '%(dest)s %(properties)s' % {'dest': self.dest,
+                                            'properties': properties_str}
+
+
+class ARPregister(collections.namedtuple(
+        'ARPregister',
+        ['ip_address', 'hw_type', 'flags', 'mac_address', 'mask', 'device'])):
+
+    def __str__(self):
+        return '%s %s %s %s %s %s' % (self.ip_address, self.hw_type,
+                                      self.flags, self.mac_address, self.mask,
+                                      self.device)

neutron_tempest_plugin/scenario/base.py

@@ -26,6 +26,7 @@ from tempest.lib.common.utils import test_utils
 from tempest.lib import exceptions as lib_exc
 
 from neutron_tempest_plugin.api import base as base_api
+from neutron_tempest_plugin.common import ip as ip_utils
 from neutron_tempest_plugin.common import shell
 from neutron_tempest_plugin.common import ssh
 from neutron_tempest_plugin import config
@@ -219,6 +220,7 @@ class BaseTempestTestCase(base_api.BaseNetworkTest):
         except lib_exc.SSHTimeout as ssh_e:
             LOG.debug(ssh_e)
             self._log_console_output(servers)
+            self._log_local_network_status()
             raise
 
     def _log_console_output(self, servers=None):
@@ -239,6 +241,12 @@ class BaseTempestTestCase(base_api.BaseNetworkTest):
                 LOG.debug("Server %s disappeared(deleted) while looking "
                           "for the console log", server['id'])
 
+    def _log_local_network_status(self):
+        local_routes = ip_utils.IPCommand().list_routes()
+        LOG.debug('Local routes:\n%s', '\n'.join(str(r) for r in local_routes))
+        arp_table = ip_utils.arp_table()
+        LOG.debug('Local ARP table:\n%s', '\n'.join(str(r) for r in arp_table))
+
     def _check_remote_connectivity(self, source, dest, count,
                                    should_succeed=True,
                                    nic=None, mtu=None, fragmentation=True,